Problem: What is the least common multiple of 54 and 42? Another way to say this is: $\lcm(54, 42) = {?}$
The least common multiple is the smallest number that is a multiple of 54 and 42. We know that 54 x 42 (or 2268) is a common multiple, but is it the least common multiple? Write out the multiples of 54 until we find a number divisible by 42. 54, 108, 162, 216, 270, 324, 378, So, 378 is the least common multiple of 54 and 42.